They've never been up for the same part before, but there's been a lot of buzz this fall that Warren Beatty might take on Arnold Schwarzenegger in hopes of stealing the role of California governor. Beatty has been making political speeches in front of conventions of nurses and college students--garnering far more publicity than Schwarzenegger's announced rivals, the state controller and treasurer, can dream about.

The Beatty boomlet is one more indication that the line between politics and entertainment has not just been blurred--it's been "obliterated." (So says Rob Reiner, the actor and film director who's also being talked of as a gubernatorial hopeful.) But just as celebrities are lending their star quality to politics, more and more real-life mayors, governors and legislators are playing themselves in films and on TV.

Last month, Los Angeles Mayor Antonio Villaraigosa played himself on "The George Lopez Show." Tony Williams, the mayor of Washington, D.C., is anxiously awaiting next year's opening of "The Sentinel," a Michael Douglas thriller in which he'll make his big-screen debut. In addition to appearing in fictional films such as "Traffic" and miniseries like "Tanner on Tanner," politicians in recent years have become fixtures on entertainment programs such as "The Daily Show."

Filmmakers have always liked casting politicians, as well as other recognizable figures such as journalists. "It provides a sort of legitimacy," says Phillip Gianos, author of "Politics and Politicians in American Film." "It adds verisimilitude and gives the audience another thing to grab on to."

It's no wonder why politicians like playing the part. There's an old joke about many of them: The most dangerous place to stand is between Senator X and a camera. But in addition to personal publicity, such appearances are often a way to promote the jurisdiction where filming is taking place. That's why Massachusetts politicians, for example, made appearances on "Cheers" and "St. Elsewhere."

Mayor Williams "is very supportive of the movies and the TV shows that come to the city, because they bring a lot of economic development," says Sharon Gang, his spokeswoman. Appearing in a D.C.- based film not only helps promote the nation's capital to viewers--and prospective visitors--around the world, she says, but also reminds show business folks that it's still a good place to shoot, despite post-9/11 security restrictions.

Politicians have a natural thirst for coverage and have learned the value of reaching voters through unconventional venues. "Our political culture now is based on TV," says Mark Crispin Miller, a media studies professor at New York University. "It's based far less on organizing among constituents or voters. We consider a politician successful to the extent that he or she plays well on TV."

There's a danger, of course, in politicians being reduced to bit players on TV. They normally operate in a world of complexity and compromise, while television is a world of black-and-white dilemmas that are resolved quickly. "I'm not sure any part of American culture can handle the need that public officials have to choose between two bad choices, as opposed to a bad and a good choice," says Alan Tonelson, a research fellow with the U.S. Business & Industry Council.

Sometimes politicians use media appearances not to blur the lines but to make evident their real-life intentions. The day before he officially announced he wouldn't make a repeat run for the presidency, Al Gore had already made it abundantly clear he wouldn't be a candidate by hosting "Saturday Night Live." "Candidate Gore would never have appeared on national TV shirtless in a hot tub," noted the Washington Post.

The moral of the story may be that even if Warren Beatty can't successfully make the leap from show business into political life, he can always jump back into film. After all, California Governor Gray Davis played himself on a sitcom not long after being recalled from office. "I wanted to ask him all sorts of questions about politics," Schwarzenegger said afterwards, "but all he wanted to do was talk about acting."